LAMMPS (3 Nov 2022)
# electrodes with equal-style ramped (electrode-)constant potential
# for graphene-ionic liquid supercapacitor

boundary p p f # slab calculation
include settings.mod # styles, groups, computes and fixes
# set boundary in main script because ffield is periodic
units real
# distribute electrode atoms among all processors:
if "$(extract_setting(world_size) % 2) == 0" then "processors * * 2"
processors * * 2

atom_style full
pair_style lj/cut/coul/long 16
bond_style harmonic
angle_style harmonic
kspace_style pppm/electrode 1e-7
# kspace_modify in main script because ffield is periodic

read_data "data.graph-il"
Reading data file ...
  orthogonal box = (0 0 -68) to (32.2 34.4 68)
  1 by 2 by 2 MPI processor grid
  reading atoms ...
  3776 atoms
  scanning bonds ...
  2 = max bonds/atom
  scanning angles ...
  1 = max angles/atom
  reading bonds ...
  640 bonds
  reading angles ...
  320 angles
Finding 1-2 1-3 1-4 neighbors ...
  special bond factors lj:    0        0        0       
  special bond factors coul:  0        0        0       
     2 = max # of 1-2 neighbors
     1 = max # of 1-3 neighbors
     1 = max # of 1-4 neighbors
     2 = max # of special neighbors
  special bonds CPU = 0.003 seconds
  read_data CPU = 0.034 seconds

# replicate 4 4 1 # test different sys sizes

variable zpos atom "z > 0"
group zpos variable zpos
1891 atoms in group zpos
group ele type 5
832 atoms in group ele
group top intersect ele zpos
416 atoms in group top
group bot subtract ele top
416 atoms in group bot

group bmi type 1 2 3
960 atoms in group bmi
group electrolyte type 1 2 3 4
1280 atoms in group electrolyte

fix nvt electrolyte nvt temp 500.0 500.0 100
fix shake bmi shake 1e-4 20 0 b 1 2 a 1
Finding SHAKE clusters ...
       0 = # of size 2 clusters
       0 = # of size 3 clusters
       0 = # of size 4 clusters
     320 = # of frozen angles
  find clusters CPU = 0.002 seconds

variable q atom q
compute qtop top reduce sum v_q
compute qbot bot reduce sum v_q
compute ctemp electrolyte temp
kspace_modify slab 3.0

variable v equal ramp(2,4)
fix conp bot electrode/conp 0.0 1.979 couple top v_v symm on etypes on
832 atoms in group conp_group

thermo 50
thermo_style custom step temp c_ctemp epair etotal c_qbot c_qtop v_v
run 500

CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE

Your simulation uses code contributions which should be cited:

- kspace_style pppm/electrode command:

@article{Ahrens2021,
author = {Ahrens-Iwers, Ludwig J.V. and Mei{\ss}ner, Robert H.},
doi = {10.1063/5.0063381},
title = {{Constant potential simulations on a mesh}},
journal = {Journal of Chemical Physics},
year = {2021}
volume = {155},
pages = {104104},
}
- fix electrode command:

@article{Ahrens2022
author = {Ahrens-Iwers, Ludwig J.V. and Janssen, Mahijs and Tee, Shern R. and Mei{\ss}ner, Robert H.},
doi = {10.1063/5.0099239},
title = {{ELECTRODE: An electrochemistry package for LAMMPS}},
journal = {The Journal of Chemical Physics},
year = {2022}
volume = {157},
pages = {084801},
}
CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE-CITE

PPPM/electrode initialization ...
  using 12-bit tables for long-range coulomb (src/kspace.cpp:342)
  G vector (1/distance) = 0.20904498
  grid = 32 32 200
  stencil order = 5
  estimated absolute RMS force accuracy = 3.7023506e-05
  estimated relative force accuracy = 1.1149519e-07
  using double precision MKL FFT
  3d grid and FFT values/proc = 151593 85504
Generated 15 of 15 mixed pair_coeff terms from geometric mixing rule
Neighbor list info ...
  update: every = 1 steps, delay = 0 steps, check = yes
  max neighbors/atom: 2000, page size: 100000
  master list distance cutoff = 18
  ghost atom cutoff = 18
  binsize = 9, bins = 4 4 16
  3 neighbor lists, perpetual/occasional/extra = 2 1 0
  (1) pair lj/cut/coul/long, perpetual
      attributes: half, newton on
      pair build: half/bin/newton
      stencil: half/bin/3d
      bin: standard
  (2) fix electrode/conp, occasional, skip from (1)
      attributes: half, newton on
      pair build: skip
      stencil: none
      bin: none
  (3) fix electrode/conp, perpetual, skip from (1)
      attributes: half, newton on
      pair build: skip
      stencil: none
      bin: none
Per MPI rank memory allocation (min/avg/max) = 22.9 | 26.72 | 30.55 Mbytes
   Step          Temp         c_ctemp         E_pair         TotEng         c_qbot         c_qtop          v_v      
         0   0              0              25137190       25137190       0.0085142912  -0.0085142912   2            
        50   17.839699      64.271283      25137031       25137215      -0.0067894391   0.0067894391   2.2          
       100   48.411618      174.41308      25136776       25137275      -0.033422174    0.033422174    2.4          
       150   70.478909      253.91515      25136658       25137384      -0.071583953    0.071583953    2.6          
       200   82.322716      296.58497      25136673       25137521      -0.11962095     0.11962095     2.8          
       250   87.739905      316.10153      25136766       25137670      -0.17281469     0.17281469     3            
       300   91.974584      331.35786      25136877       25137825      -0.22657123     0.22657123     3.2          
       350   100.73048      362.90284      25136949       25137987      -0.27817429     0.27817429     3.4          
       400   111.78597      402.73256      25137004       25138156      -0.32659395     0.32659395     3.6          
       450   122.14181      440.04167      25137066       25138324      -0.37054363     0.37054363     3.8          
       500   127.32331      458.70912      25137171       25138482      -0.40653009     0.40653009     4            
Loop time of 49.2075 on 4 procs for 500 steps with 3776 atoms

Performance: 0.878 ns/day, 27.337 hours/ns, 10.161 timesteps/s, 38.368 katom-step/s
75.7% CPU use with 4 MPI tasks x no OpenMP threads

MPI task timing breakdown:
Section |  min time  |  avg time  |  max time  |%varavg| %total
---------------------------------------------------------------
Pair    | 5.7517     | 5.9151     | 6.0961     |   6.6 | 12.02
Bond    | 0.0011959  | 0.0013362  | 0.0014512  |   0.2 |  0.00
Kspace  | 24.223     | 24.404     | 24.566     |   3.2 | 49.59
Neigh   | 0.10283    | 0.10288    | 0.10301    |   0.0 |  0.21
Comm    | 0.30801    | 0.31944    | 0.33141    |   2.0 |  0.65
Output  | 0.0010416  | 0.0014127  | 0.0024086  |   1.5 |  0.00
Modify  | 18.405     | 18.418     | 18.432     |   0.3 | 37.43
Other   |            | 0.04459    |            |       |  0.09

Nlocal:            944 ave         951 max         941 min
Histogram: 1 2 0 0 0 0 0 0 0 1
Nghost:        5924.75 ave        5941 max        5910 min
Histogram: 1 0 0 1 0 1 0 0 0 1
Neighs:         431570 ave      442073 max      419253 min
Histogram: 1 1 0 0 0 0 0 0 0 2

Total # of neighbors = 1726280
Ave neighs/atom = 457.17161
Ave special neighs/atom = 0.50847458
Neighbor list builds = 7
Dangerous builds = 0
Total wall time: 0:00:55
